I was comparing phones with a friend, an iPhone friend, and I was showing the task killer and how the available memory rises as I kill apps that are running in the background (if that's what's really happening). He mentioned that the iPhone doesn't do that, when you exit out of an app, it's done and it's not running anywhere. Is this true? Also, is there a setting that allows our memory to remain freed up when we exit out of an app? Why do we need them running all the time?